Method and means of improving firearm accuracy



J. H. MONROE 3,3 50,807

METHOD AND MEANS OF IMPROVING FIREARM ACCURACY Nov. 7, 1967 Filed May 26, 1966 qluuuuuuuul now United States Patent Oflice Drive,

ABSTRACT OF THE DISCLGSURE To increase the accuracy of firing a rifle, the barrel is anchored at its rear portion to the stock. With the stock clamped in fixed position the outer end of the barrel is then flexed upwardly away from the stock. While the barrel is under cantilever flexure the space between the stock and the barrel is filled with a self-curing resin material consisting of fiber glass and a resin of the epoxy type. When the resin is cured the barrel will be retained in its flexed position. Thus, the barrel is retained slightly flexed during normal use to minimize vibration and to assure that the barrel remains in fixed position relative to the stock during successive firings.

This invention relates to improvements in firearms, and more particularly to an. improved gun stock having a barrel-receiving portion which, upon securement of the barrel therein, provides for the application to the gun barrel of flexing forces which maintain the barrel under stress during normal use of the firearm.

The problem of variable accuracy in the firing of a rifle has long been recognized by those skilled in the art. Accuracy is aifected by change in bullet weights, varying powder charges and particularly by vibration of the barrel which occurs after firing and which gives rise to variable positioning of the barrel with respect to the stock. It has been proposed, Brown et al. Patent 3,060,612 and Klipsch Patent 2,205,982, to provide springs which may be stressed as may be desired to apply the resultant spring forces to the barrel to maintain upon it a predetermined stress.

In accordance with the present invention, advantage is taken of the fact that the barrel itself is made of a resilient material, normally steel, and hence by securely holding the gun stock in fixed position, the barrel may be mounted thereon and then placed under stress adequate to produce deflection of the barrel away from the gun stock by a slight amount. With the barrel in its flexed position, there is molded into an elongated arcuate area of the gun stock a plastic material, such as a mixture of fiber glass and an epoxy resin, which then hardens with its exposed surface conforming with the flexure of the barrel. The result is that thereafter, when the gun barrel is assembled to the stock, it is placed under the same flexing forces. In this manner, there is produced a high degree of damping of vibrations and a mounting for the barrel which is invariable;These factors all contribute to a uniformity and high degree of precision in the repeated firing of the rifle.

For further objects and advantages of the invention and for an explanation as to how there may be practiced the methods forming a part of the invention, reference is to be had to the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an exploded view of a barrel assembly, a clamping device and a gun stock securely clamped in fixed position, preparatory to mounting the barrel therein;

FIG. 2 is a side view of the assembly of FIG. 1 with the barrel in its stressed position for application to the gun stock of the plastic molding material; and

FIG. 3 is an enlarged sectional view taken on the line 33 of FIG. 2 showing the curved plastic material in place.

Patented Nov. 7, 1%57 Referring now to the drawings, a barrel assembly 10 has been illustrated in FIG. 1 including a barrel 12, a trigger subassembly 13 and a bolt subassembly 14. It is to be noted that the barrel has formed integral therewith threaded openings 12a and 12b for receiving mounting screws to secure the barrel to the stock 15. It is to be understood that the barrel assembly and the stock 15 have been more or less diagrammatically illustrated since the invention is broadly applicable to firearms of all types in which a barrel is carried by a stock.

In order to maintain the barrel 1?. under flexing forces during normal use of the firearm, the following procedures are utilized. The stock 15 has its shoulder portion resting between the two arms of a clamp 16, only the near one being shown in the drawings. The lower part of the shoulder portion of the stock 15 rests upon a clamping screw 17, and the two arms of the clamp 16 are tightly pulled together by means of a wing nut 18. The forward end of the stock 15 rests upon a clamping screw 10 which is similarly provided with a Wing nut 19a, FIG. 2, for tightening together the two arms 20a and 26b of a second clamp 20. These clamps have been shown diagrammatically, it being understood that any suitable clamping means to maintain the stock in secure fixed position will be suitable. In some instances, it may be desirable to have the lower left-hand corner of the stock rest upon the base B, in which event the forward clamping means 20 will be of somewhat lesser height. In practice, it may also be desirable to provide the bolts 17 and 19 with cushioning material as of a rubber-like cylinder. Alternatively, flat surfaces may be utilized to minimize any possibility of marring any part of the stock during the operations now to be described. In this connection, rubber-like material may be utilized on the faces of the clamps which will preferably be shaped so that their surfaces are complementary to those of the stock in the locations engaged by the clamping means 16 and 20.

With the stock 15 securely held in fixed position by the clamping means 16 and 20, the barrel assembly 10 is now positioned in place on the stock. That portion of the stock extending from the region of the threaded opening 12a to its forward end has an annular portion 15a of much larger diameter than the barrel to provide a relatively large elongated cavity in which molding material, preferably fiber glass including a resin of the epoxy type, is to be poured.

In FIG. 2, the barrel has been shown in place in the gun stock. A pair of mounting screws 21 and 22 with hexagonal heads tightly hold the rear portion of the barrel in fixed position within the gun stock. These screws 21 and 22 are provided with hexagonal heads for ease in producing the requisite tightening forces and also for ease in removal after the completion of the flexure-producing operations. It will be further noted that these screws extend through openings in the trigger guard plate 23, thus to protect the gun stock from deformation upon tightening of said screws. With the gun stock 15 tightly clamped in rigid position, a jack 24 of the screw type, also supported from the common base member B, is utilized to place the barrel 12 under stress. The jack 24 is operated as by a lever 24a to raise the upper end 24b. It presses against the gun barrel 12 to flex it upwardly through the distance indicated at 25. This degree of cantilever flexure or strain indicated by the flexing distance 25 is not particularly critical. It will vary with different rifles, depending upon the caliber, weight and the nature of the resilient material of which they are fabricated.

In accordance with the invention, the flexure is of a measurable amount and produces flexure of the barrel 12 from the region of the jack 24 rearwardly to the region where the screw 22 has tightly anchored the barrel against the stock 15. With the barrel under the illustrated strain, i.e., discrete flexure thereof, the enlarged elongated cavity a is filled with a resin which is self-curing, such as the above mentioned fiber glass in mixture with an epoxy resin. I have found that with an epoxy resin fiber glass, the cavity 15a provides, after curing, a hardened surface which may be described as in wetting engagement with the gun barrel, i.e., it hardens without shrinkage and with an exposed surface conforming with the flexure of the barrel throughout the forwardly extending portion of the gun stock. The gun stock itself will preferably extend toward the end of the gun barrel and will terminate as short a distance as is reasonable in order to obtain the full advantage of the invention in diminution of vibrational effects due to firing. Conventional lengths of gun stocks will be satisfactory, though those of longer dimension will be preferred.

Alternatively, the cavity 15a may be filled with the mixture 15b of fiber glass and resin as indicated in FIG. 1, and the barrel then mounted in the gun stock as previously described. The one difference, however, will be that the jack 24 will have its pressure head 2412 located in its final position. Thus, the barrel 12 will be pulled by the cap screws 21 and 22 downwardly to set the rear end of the barrel against the complementary supporting surfaces of the gun stock, while at the same time producing the flexure of the forward end of the barrel through the distance 25. It is in this way that there is produced the wetting engagement of the fiber glass epoxy resin with the gun barrel and which assures in effect the wetting engagement between the molding material and the lower surface of the gun barrel throughout the length 12a of the cavity 15a.

After the curing and hardening of the resin within the elongated cavity 15a, the tension applied by the jack 24 is removed. Thereafter, the screws 21 and 22 are removed. In general, no further finishing is required, but where needed, the upper surface of the hardened resin can be finished as by smoothing the upper surface along the edges of cavity 15a. Thereafter, the normally used screws for mounting the barrel to the gun stock and including the trigger assembly will be applied. Upon tightening the mounting screws corresponding with the illustrated temporarily used screws 21 and 22, the barrel 12 will again be placed under the same tension as during the special forming of the supporting surface. Thus, the barrel will again be flexed through the length indicated by the dimensional arrows 120. With the barrel thus restressed and maintained under strain, there will be achieved a high degree of precision in subsequent firing of ammunition of the same or of differing power and bullet weight.

Now that the principles of my invention have been explained, it will be understood that the rifle barrel may be mounted in any suitable manner to maintain the barrel in strain, discrete flexure, while the gun stock as a whole is molder as a single part. The molding composition may be fiber glass impregnated with an epoxy resin, or other molding compositions proposed for gun stocks may be utilized. These include resins of many types, preferably with fillers, such as fiber glass, to increase their strength and to enhance their damping effects on barrel vibration.

As a further alternative, a molding part may be prefabricated to correspond with the configuration of the gun barrel in its flexed state, and such molding part utilized in place of the gun barrel, either for the added molding material, as explained above, or in the molding of the complete gun stock in a single operation. In each modification, the important element of the invention is the configuration of the gun stock in the region of its barrel-engaging portion, together with the fastening screws which assure the flexure of the barrel to eliminate, or at least greatly minimize, all vibrations and to assure increased accuracy in the firing of the same.

What is claimed is:

1. A firearm including an elongated barrel and a gun stock having a supporting portion for the rear portion of said barrel and a-flexure-producing portion coextensive with a major length of said barrel, said flexure-producing portion having a surface complementary to that of the gun barrel when placed under cantilever flexing forces of magnitude sufficient to produce slight flexure thereof in a direction away from said gun stock, and fastening means connecting the rear portion of said barrel to said gun stock for flexing said barrel to conform with said surface and for securing said barrel to said gun stock.

2. A firearm including an elongated barrel and a gun stock having a supporting portion for the rear portion of said barrel and a flexure-producing portion coextensive with a major length of said barrel,

said flexure-producing portion having a cross-sectional shape along its length complementary to the external surface of the barrel to be received therein and which barrel-receiving portion lengthwise thereof has an outwardly inclined configuration,

said outwardly inclined configuration of said stock corresponding with cantilever flexure of the barrel from a rear portion thereof in a direction away from said gun stock, and

fastening means for anchoring said rear portion of said barrel to said gun stock and for producing said cantilever flexure of said barrel to move its external surface into engagement with said complementary surface of said barrel-receiving portion throughout said major length of said barrel.

3. The method of producing gun barrels which comprises,

supporting the gun stock in fixed position with the rear portion of the barrel secured to said gun stock, said gun stock having a cavity extending throughout a major length of said barrel,

applying a flexing force on the unsupported end of said barrel in a direction to produce cantilever flexure of said barrel in a direction away from said cavity, while said barrel is flexed, filling said cavity with a selfcuring resin material, and after curing of said resin material to provide a hardened surface complementary to that of said flexed gun barrel removing said stock and gun barrel from said supporting means whereby the said gun barrel during normal use is maintained under said cantilever gun stocks for elongated flexure.

References Cited UNITED STATES PATENTS 2,205,857 6/ 1940 Marchand 42 2,339,331 1/1944 Crigg 42-75 2,372,568 3/1945 Crigg 42-75 2,404,904 7/ 1946 Collins 42-75 2,479,594 8/1949 Yasho 4275 2,967,368 1/1961 Williams 4275 BENJAMIN A. BORCHELT, Primary Examiner. 

1. A FIREARM INCLUDING AN ELONGATED BARREL AND A GUN STOCK HAVING A SUPPORTING PORTION FOR THE REAR PORTION OF SAID BARREL AND A FLEXURE-PRODUCING PORTION COEXTENSIVE WITH A MAJOR LENGTH OF SAID BARREL, SAID FLEXURE-PRODUCING PORTION HAVING A SURFACE COMPLEMENTARY TO THAT OF THE GUN BARREL WHEN PALCED UNDER CANTILEVER FLEXING FORCES OF MAGNITUDE SUFFICIENT TO PRODUCE SLIGHT FLEXURE THEREOF IN A DIRECTION AWAY FROM SAID GUN STOCK, AND FASTENING MEANS CONNECTING THE REAR PORTION OF SAID BARREL TO SAID GUN STOCK FOR FLEXING SAID BARREL TO CONFORM WITH SAID SURFACE AN FOR SECURING SAID BARREL TO SAID GUN STOCK. 